Heron's fountain

This video is a mess. But I like it.

Okay, you see what's going on here. Water drains from the top and gravity takes it down to the bottom. The bottom is the air supply tank that's filling with water. 

He doesn't mention that the weight of the water inside the longest tube is part of the pressure that's forcing the air. The longer that hose then the more force of air. (Air is compressible but water is not.) This is important factor in siphoning. 

For example, I can start a siphon from the aquarium to the toilet more easily by filling a hose with water from the sink into the aquarium then stopping it, plugging the end with my thumb, and carrying the hose heavy with water to the toilet and letting the weight of the water in the tube along with gravity pressing down on the aquarium and the propensity of water to find its level to pull water from the aquarium into the toilet, than I can by placing an empty hose into the aquarium and sucking out air until water lifts over the edge of the aquarium and fill the hose sufficiently for its weight in the hose to keep pulling water and pushing out air into the toilet. That is, the weight of a filled hose is easier than sucking on an empty hose. Either way it's kind of fun.  

He doesn't mention this is not a perpetual machine. Eventually the air supply bottle runs out of air because the bottle is filled with water. And the water bottle supply is drained of water.

So this fountain runs a few minutes then ends. What fun is that? Come on! 

We need a perpetual Heron's fountain. An improved Heron's fountain. Why did Heron give up? Because everything that he tried failed. 

Now you're thinking, if the bottle supplying air runs out of air and fills up with water, and the bottle supplying water runs out of both, then why not connect them so that the air supply bottle filling up with water gives water to the depleting water supply bottle? 

Duh. 

The best plans seem so right in the mind or on paper but fail in actuality. I think the problem will have to do with the weight of the water inside the longest tube. But I'm not sure without actually trying. Heron's fountain relies on the compressibility of air. If water is equalizing between the two bottles then perhaps that compression is forfeited. Water seeking its own level by gravity displaces the force of compressed air that makes Heron's fountain work.

Still with this?